CVE-2017-1000451 in fs-git
Summary
by MITRE
fs-git is a file system like api for git repository. The fs-git version 1.0.1 module relies on child_process.exec, however, the buildCommand method used to construct exec strings does not properly sanitize data and is vulnerable to command injection across all methods that use it and call exec.
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Analysis
by VulDB Data Team • 12/19/2019
The vulnerability identified as CVE-2017-1000451 affects the fs-git module version 1.0.1, which provides a file system-like API for interacting with git repositories. This module utilizes the child_process.exec function to execute system commands, creating a potential attack vector through improper input sanitization. The core issue lies within the buildCommand method that constructs execution strings without adequate validation or sanitization of user-provided data, allowing malicious inputs to be interpreted as shell commands rather than literal strings. This fundamental design flaw exposes the system to command injection attacks that can be leveraged by unauthorized users to execute arbitrary code on the affected system.
The technical implementation of this vulnerability stems from the module's reliance on child_process.exec for executing git operations, which inherently poses security risks when user input is directly incorporated into command strings without proper sanitization. The buildCommand method serves as the primary attack surface where unvalidated data enters the command construction process, making all methods that utilize this function susceptible to injection attacks. When an attacker can manipulate the input parameters passed to these methods, they can inject malicious shell commands that will be executed with the privileges of the process running the fs-git module, potentially leading to complete system compromise.
From an operational perspective, this vulnerability creates significant risks for systems that utilize the fs-git module, particularly in environments where repository operations are performed with elevated privileges or where the module handles untrusted input from external sources. The impact extends beyond simple code execution to potential data exfiltration, system reconnaissance, and persistence mechanisms that attackers can employ to maintain access. The vulnerability affects the entire attack surface of any application using the module, as all methods that invoke buildCommand are exposed to the same injection risk, making it a critical security concern for any system relying on git-based file system operations.
Mitigation strategies for CVE-2017-1000451 should focus on eliminating the use of child_process.exec with unsanitized input and implementing proper input validation and sanitization measures. The recommended approach involves replacing the vulnerable buildCommand method with a safer implementation that avoids shell command construction entirely, instead using direct git command interfaces or properly escaped parameter passing. Organizations should also consider updating to newer versions of the fs-git module that address this vulnerability, implementing proper input validation at multiple layers, and following the principle of least privilege when executing git operations. This vulnerability aligns with CWE-78, which specifically addresses improper neutralization of special elements used in OS commands, and represents a classic example of command injection as categorized in the ATT&CK framework under the execution tactic, where adversaries leverage such vulnerabilities to run malicious commands on target systems.